Time Wasters

Just wondering why it is that some people waste so much time while playing at unimportant tables? I'm talking about people who get into regular 9 person play chip Sit N Go's and let the clock run down each and everytime it is their turn. From pre-flop all the way through the river or until they decide to fold. I know that sometimes people do it to make their opponets think they have a playable hand but to let the clock run down EVERYTIME justs seems like going way overboard to me.
Any comments?

My theory is that they are multi-tasking. Either multi-tabling, talking on the phone, watching TV, checking email (or forums like this), etc., etc. It think it is rarely someone doing it on purpose.

Another thought.
By wasting time, they put folks on edge. Everyone knows the blinds are time dependant, and will feel a sence of urgency when they can bet.
Add that to the fact that it is often possible to get ITM by folding all the hands in a 9 seat sng, and you might have the why of it all.

Maybe to see who is impatient enough to type something in the chat complaining?=loose play

lol Just a theory of course. I think it works against you if you do it anyway. It's not good when the whole table is mad at you and looking to take you out with any two cards.